Propeller



April 10, 1934. M. A. CUTOLO PROPELLER Filed June 16 1932 2 Sheets-Sheetl Inventor a mrz'o i [262020 M M. A. CUTOLO April 10, 1934.

PROPELLER 2 Sheets-Sheet 2 Filed June 16, 1932 Inventor Q By Wm flflomeyPatented Apr. 10, 1934 STATES PATENT OFFICE 8 Claims;

My invention relates to improvements in pro pellers, and an importantobject of the invention is to provide a propeller of maximum efficiencywith smallest bulk, and low cost and ease of manufacture.

Another important object of my invention is to provide a propellerhaving these desirable characteristics and also the capabilityof beingmade in one piece, or of several pieces of material.

It is also an important object of my invention to provide a propellerhaving these features, wherein a plurality of foils making up a pair ofblades provided, the foils or planes being related to each other as towidth, pitch, and length, so

" as to obtain the maximum aero-dynamic effect within the limits ofefflciency.

Other objects and advantages of my invention will be apparent from areading of the following description in connection with the drawings,wherein for purposes of ilustration I have shown a preferred embodimentof the invention.

In the drawings:--

Figure 1 is a front elevational view of the embodiment which indicatesthe relationships of the planes of each blade.

Figure 2 is an edge elevation of the embodiment.

Figure 3 is a side elevational view thereof.

Figure 4 is a sectional view taken approximately on the line 44 ofFigure 1.

Figure 5 is a sectional view taken approximately on the line 55 ofFigure 1.

Figure 6 is a perspective view of the embodiment.

Referring in detail to the drawings, wherein like numerals refer to likeparts throughout the same, the numeral 5 generally designates theembodiment of the invention, the numeral 6 one blade thereof and thenumeral '7 the other blade thereof.

Each blade 6, '7 may be said to be composed of three sub-blades orplanes, 6a, 6b, and 6c, and 7a, 7b, and 70, respectively.

If desired opposing sub-blades such as subblades 6a and 7a may beconstituted by a single F ordinary propeller, the device beingconstructed by placing propellers of successively reduced size onebehind the other on the same axis. While it is expressly included withinthe invention to so form the propeller of the invention in this manner,a specific provision of the invention is to provide the inventionconstructed of a single piece of material, the form and arrangementthereof being especially adapted to such economical and mechanicallyefficient construction.

Each of the sections which are constituted by opposing sub-blades suchas the section 6a, 7a, the section 622, 7b, and the section 60, 7c, aresimilar in cross section, length, width, and pitch. However, eachsection differs from its neighbor in width, length, and if desired, inpitch.

In a desirable arrangement, the section Go, To may have a maximum Widthof 27 degrees of a circle, the section 612, '71) maximum width ofdegrees of a circle, the section 60, 7c maximum Width of 24 degrees of acircle. Taking the length of the section 6a, m, as the criterion, thesection 6b, 7b will have blades having a ten percent less length thanthe blades of the section 611, 7a, while the section 61), lb will haveblades of a length ten percent less than the length of the blades in thesection 6b, 7b.

The front elevation of each of the sections is typified by that ofsection 6a, 7a, Figure 1. However, the blades of the succeeding sectionsare placed as indicated in Figure 5 so as to meet the neighboring edgesof the neighboring sections. Toward the outer ends of the blades someseparation between the edges of the blades obtains as indicated by thesectional View, Figure 4.

Adjacent the hub portion of the embodiment generally indicated 8, thehub portions 9, 10, 11 of the blade 6, the hub portions 12, 13, 14 ofthe blade 7, are culped and concaved as shown in the drawings, so thatthe hub formation resulting from such treatment of the inner endportions of the sub-blades is substantially continued as an axiallyextended cylindrical formation which is best seen in the perspectiveFigure 6. This gives a continuous aero-dynamic surface, and provides forcontinuity in the pressures exerted by the device of the inventionagainst the medium in which it is operated.

As indicated in the sectional views in Figures 4, 5, the sub-blades arerelatively thin, and each of them in each blade has its own curvatureand displacement. As seen the cross sections are somewhat reduced insuccessive sub-blades away from the sub-blades of the section 6a, 711.

It will be observed that each blade 6, 7 occupies approximately '76degrees of the circle which defines the sphere of action of thepropeller, so that the sum of the acting blades of the device of theinvention is that corresponding to 152 degrees of the sphere of action.Due to the fact that the construction furnishes main blades which aresuperior to merely wide blades of the same width as the sum of the widthof the sections of the invention, the difficulties ordi narily met within the construction and operation of such ordinary wide bladedpropellers are obviated in the case of the invention by the peculiarformations thereof as described above.

It will be observed that the action of the propeller of the invention isnot the same as the action of a propeller constructed with a pair ofsingle, undivided blades, since the successive subblades arescientifically reduced to have a specific aero-dynamic compensationwhich obviates the unequal action characteristic of wide bladedpropellers. At the same time, a greater power can be exerted upon amedium through the use of a propeller of the invention than can beachieved by wide bladed propellers not having such compensatorycharacteristics.

The device of the invention may be constructed of metal or of anysuitable composition, and the design of the principles thereof appliedand used in any place and for any work requiring a propeller or similardevice operating in a fluid medium.

Though I have shown and described herein a preferred embodiment of theinvention, it is to be definitely understood that I do not desire tolimit the application of the invention thereto, and any change orchanges may be made in material and structure and arrangement of parts,within the spirit of the invention and the scope of the subjoinedclaims.

What is claimed is:

1. A propeller comprising an elongated hub, a plurality ofcircumferentially spaced blades on said hub, each of said bladesconsisting of a plurality of sub-blades projecting radially from andmerging into said hub, said sub-blades arranged one behind the other anddecreasing progressively in length from front to rear, said sub-bladeshaving a portion of their adjacent edges connected together from saidhub to a point radially outward of said hub but inward of the outer endsof said sub-blades, the remaining portions of said adjacent edges beingspacec apart.

2. A propeller comprising an elongated hub having circumferentiallyspaced blades thereon, each of said blades consisting of a plurality ofsub-blades arranged one behind the other and circumferentially arrangedso as to avoid overlapping each other, said sub-blades having a portionof their adjacent edges connected from said hub to a point radiallyoutwardly removed from said hub but spaced inwardly from the outer endsof said adjacent edges, the remaining portion of said adjacent edgesbeing circumferentially and axially spaced.

3. A propeller comprising an elongated hub having circumferentiallyspaced blades thereon, each of said blades comprising a plurality ofsub-blades arranged one behind the other along and merging into said huband being successively radially shorter from front to rear, saidsub-blades being circumferentially displaced so as to avoid overlappingthereof, a portion of adjacent edges of adjacent blades extending fromsaid hub to a point radially outward from said hub but inward from theouter end of said adjacent edges being connected, the remaining portionof said adjacent edges being separated.

4. A propeller comprising an elongated hub having circumferentiallyspaced blades thereon,

each of said blades comprising a plurality of sub-blades arranged onebehind the other along and merging into said hub and being successivelyradially shorter from front to rear, said sub-blades beingcircumferentially displaced so as to avoid overlapping thereof, aportion of adjacent edges of adjacent blades extending from said hub toa point radially outward from said hub but inward from the outer end ofsaid adjacent edges being connected, the remaining portion of saidadjacent edges being separated, each of said sub-blades having a convexface and a concave face, the convex and concave faces of adjacentsub-blades merging where said adjacent edges are connected.

5. A propeller comprising an elongated hub having circumferentiallyspaced blades thereon, each of said blades comprising a plurality ofsubblades arranged one behind the other along and merging into said huband being successively radially shorter from front to rear, saidsub-blades being circumferentially displaced so as to avoid overlappingthereof, a portion of adjacent edges of adjacent blades extending fromsaid hub to a point radially outward from said hub but inward from theouter end of said adjacent edges being connected, the remaining portionof said adjacent edges being separated, the said remaining portion ofthe forward one of the edges of each of said sub-blades being radiallyoutwardly and rearwardly curved, and the said remaining p rtion of theback one of the edges of each of said sub-blades being relativelystraight.

6. A propeller comprising a hub, a plurality of circumferentially spacedblades extending therefrom, each of said blades comprising a unitconsisting of a plurality of edge to edge connected sub-blades ofcircumferentially successively smaller length, said sub-blades beingarranged along said hub, outer portions of adjacent side edges ofadjacent ones of said subblades being circumferentially and axiallyspaced with respect to said hub.

7. A propeller comprising a hub, a plurality of circumferentiallyvspaced blades extending therefrom, each of said blades comprising a unitconsisting of a plurality of edge to edge con-- nected sub-blades ofcircumferentially successively smaller length, said sub-blades being arranged along said hub, outer portions of adjacent side edges of adjacentones of said sub-blades being circumferentially and axially spaced withrespect to said hub, the forward ones of said outer portions beingradially outwardly and rearwardly curved.

8. A propeller comprising a hub, a plurality of circumferentially spacedblades extending therefrom, each of said blades comprising a unitconsisting of a plurality of edge to edge con-- nected sub-blades ofcircumferentially succes sively smaller length, said sub-blades beingarranged along said hub, outer portions of adjacent side edges ofadjacent ones of said subblades being circumferentially and axiallyspaced with respect to said hub, the forward ones of said outer portionsbeing radially outwardly and rearwardly curved, the rearward ones ofsaid outer portions being substantially straight.

MARIO ALESSANDRO CUTOLO.

